Porto beat an under-strength Arsenal [Images] side 2-0 on Wednesday to clinch top spot in Group G of the Champions League.

With the two teams already guaranteed a place in the first knockout round, Arsenal manager Arsene Wenger, in his 700th game in charge of the London [Images] side, rested several first choice players and chose to field young reserves instead.

The home side opened the scoring when defender Bruno Alves headed home a Raul Meireles corner after 39 minutes and doubled their lead thanks to a fine finish from Argentina striker Lisandro Lopez on 54 minutes.

The victory gained some revenge for the Portuguese champions 4-0 defeat at Arsenal in September.

"Our tactics were stronger and we had an excellent second half," Porto's coach Jesualdo Ferreira told Portuguese television.

"I don't recall any goal opportunity for Arsenal. We deserved to win and the victories in the last three qualifying matches serve to give us confidence for the knockout phase"

After an even opening half hour of few chances, Alves's goal was all too easy as he rose unmarked to score Porto's first goal against Arsenal in their fourth Champions League meeting.

Lopez then latched onto a deft through ball from midfielder Fernando to ensure Porto's unbeaten home record against English club's stretched to 12 matches.

Arsenal's best chance for a consolation goal came two minutes from time when they were awarded a free kick on the edge of the area but Denmark striker Nicklas Bendtner feebly struck the set-piece straight at Brazil [Images] goalkeeper Helton.

"Many of our player have little injuries and we know in the championship we are in a position where every game is vital to us and that's what we decided to protect them this week," Wenger told Sky Sports, defending his selection.